1. Field of the Invention
The present invention relates to a decorative sheet having pearl-like brilliance, and a decorative material having this decorative sheet laminated on a base material such as a resin molded body and the like. Particularly, the present invention relates to a decorative sheet and decorative material having excellent weather resistance, suitable for uses requiring high weather resistance performance such as automobile interiors and other uses.
2. Description of the Related Art
Decorative sheets are used in various uses such as construction interior and exterior materials, construction materials, furniture, or automobile interior and exterior materials and the like. Decorative sheets are often required to have weather resistance, paint feeling and the like. In such cases, an acrylic resin sheet excellent in transparency is used as a base material sheet on the front surface side. For example, as a decorative sheet capable of being molded and laminated on the surface of a resin molded item and the like, a decorative sheet and the like having configuration of the following layers laminated in this order (see, Japanese Patent Application Laid-Open (JP-A) No. 2001-232660) can be listed: on the surface side, a transparent acrylic resin sheet; an ink layer having a design expressed using a mixture, of an acrylic resin and a vinyl chloride-vinyl acetate copolymer, as a binder resin; an adhesive layer using a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a binder resin; and as a resin sheet on the back side, a resin sheet having a coloring masking property of an ABS resin (acrylonitrile-butadiene-styrene copolymer).
To express a design of a decorative sheet, brilliance such as metal gloss feeling, pearl gloss feeling and the like, are required in some cases. For imparting such brilliance to a decorative sheet, a metal vacuum evaporation layer is provided in some cases. However, brilliant pigments such as a metal powder, pearl pigment and the like are often contained in an ink layer, resin sheet and the like is contained in the ink layer, the resin sheet or the like (see, JP-A No. 2002-210907) in many cases. As the brilliant pigment to be used, a powder of a metal such as aluminum and the like is used when a metal gloss feeling is expressed as a brilliance property, a pearl pigment such as titanium dioxide coated mica and the like is use when a pearl gloss feeling is expressed, in general.
Though a pearl gloss feeling gives a luxurious feeling as compared with a metal gloss feeling, when titanium dioxide coated mica which is a general pearl pigment is used, there occurs a problem of deterioration of the weather resistance. When the weather resistance is deteriorated, there will be a failure that a decorative sheet or decorative material is peeled off at a pearl ink layer containing an added pearl pigment. When the weather resistance is deficient, measures are usually taken that a resin excellent in the weather resistance such as an acrylic resin and the like is used as the resin of a base material sheet, or an ultraviolet absorber or a light stabilizer such as a bindered amine-based radical scavenger and the like is added in the resin of a base material sheet. However, these countermeasures are limited since the light stabilizer tends to bleed out from the surface to cause whitening and the like.
For evaluation of the weather resistance, an artificial accelerated exposure test imitating an atmospheric exposure test at laboratory level is common, since a result of good reproducibility is obtained in a shorter period of time. And as its test light source, a sunshine carbon arc lamp is often used for a long time. However, a xenon arc lamp gives a result closer to weather resistance under natural environments than the sunshine carbon arc lamp. Therefore, particularly currently, a test by a xenon arc lamp tends to be adopted when weather resistance is evaluated more precisely. For example, there may be a case, though the weather resistance performance evaluated by the sunshine carbon arc lamp is excellent, the weather resistance performance is poor when evaluated by the xenon arc lamp.